The present disclosure is generally related to imaging members, also referred to as photoreceptors, photosensitive members, and the like, and in embodiments to methods of treating the charge generation layer of electrophotographic imaging members. The imaging members may be used in copier, printer, fax, scanner, multifunction machines, and the like. In embodiments, the methods reduce scratching, abrasion, corrosion, fatigue, and cracking, and facilitate cleaning and durability of devices, for example active matrix imaging devices, such as active matrix belts.
In the art of electrophotography, a photoreceptor, imaging member, or the like, comprising a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging the surface of the photoconductive insulating layer. The photoreceptor is then exposed to a pattern of activating electromagnetic radiation such as light, which selectively dissipates the charge in the illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in the non-illuminated areas. This electrostatic latent image may then be developed to form a visible image by depositing finely divided electroscopic toner particles on the surface of the photoconductive insulating layer. The resulting visible toner image can be transferred to a suitable receiving member such as paper. This imaging process may be repeated many times with reusable photoconductive insulating layers.
Electrophotographic imaging members or photoreceptors are usually multilayered photoreceptors that comprise a substrate support, an electrically conductive layer, an optional hole blocking layer, an optional adhesive layer, a charge generation layer, and a charge transport layer in either a flexible belt form or a rigid drum configuration. Multilayered flexible photoreceptor members may include an anti-curl layer on the backside of the substrate support, opposite to the side of the electrically active layers, to render the desired photoreceptor flatness.
Examples of photosensitive members having at least two electrically operative layers including a charge generating layer and diamine containing transport layer are disclosed in U. S. Pat. Nos. 4,265,990; 4,233,384; 4,306,008; 4,299,897; and 4,439,507, the disclosures of each of which are hereby incorporated by reference herein in their entireties.
Photoreceptors can also be single layer devices. For example, single layer organic photoreceptors typically comprise a photogenerating pigment, a thermoplastic binder, and hole and electron transport materials.
As more advanced, higher speed electrophotographic copiers, duplicators and printers were developed, the performance requirements for the xerographic components increased. Moreover, complex, highly sophisticated, duplicating and printing systems employing flexible photoreceptor belts, operating at very high speeds, have also placed stringent mechanical requirements and narrow operating limits as well on photoreceptors.
The charge generation layer is capable of photogenerating holes and injecting the photogenerated holes into the charge transport layer. The charge generation layer used in multilayered photoreceptors include, for example, inorganic photoconductive particles or organic photoconductive particles dispersed in a film forming polymeric binder. Inorganic or organic photoconductive material may be formed as a continuous, homogenous charge generation section. Many suitable photogenerating materials known in the art may be used, if desired.
Electrophotographic imaging members or photoreceptors having varying and unique properties are needed to satisfy the vast demands of the xerographic industry. The use of organic/inorganic photogenerating pigments such as phthalocyanines, perylenes, bisazos, perinones, and polycyclic quinines in electrophotographic applications is well known. Generally, layered imaging members with the aforementioned pigments exhibit acceptable photosensitivity.
However, faster pigments are desired for future photoreceptor device designs as process speeds increase.
There is remains a need to straightforwardly adjust pigment sensitivities. The ability to tailor sensitivities has been previously demonstrated to be a valuable capability by involving the mixing of high and low sensitivity pigments. The problem is to find a common polymeric binder to disperse two pigments with excellent dispersion quality.
Common print quality issues are strongly dependent on the quality of the charge generation layer. For example, charge deficient spots and bias charge roll leakage breakdown are problems that commonly occur. Another problem is imaging ghosting which is thought to result from the accumulation of charge somewhere in the photoreceptor. Consequently, when a sequential image is printed, the accumulated charge results in image density charges in the current printed image that reveals the previously printed image.
U.S. Pat. No. 6,350,550, which is incorporated by reference herein in its entirety, describes in the Abstract thereof a charge generation section of an electrophotographic imaging member having hydroxygallium phthalocyanine photoconductive pigment and benzimidazole perylene photoconductive pigment in a solvent solution comprising a film forming polymer or copolymer dissolved in a solvent.
U.S. Pat. No. 6,063,553, which is incorporated by reference herein in its entirety, describes in the Abstract thereof an electrophotographic imaging member including a supporting substrate; an undercoat layer; a charge generation layer comprising photoconductive pigment particles, film forming binder and a charge transport layer formed from a coating solution, the coating solution comprising charge transporting molecules, the charge transporting molecules comprising a major amount of a first charge transport molecule comprising an alkyl derivative of an arylamine and a minor amount of second transport molecule comprising an alkyloxy derivative of an arylamine, the charge generation layer being located between the substrate and the charge transport layer. A process for fabricating this imagine member is also disclosed.
U.S. Pat. No. 5,350,654, which is incorporated by reference herein in its entirety, describes in the Abstract thereof a layered photoreceptor composed of a substrate, an extrinsic pigment layer that has been sensitized disposed over the substrate, and a charge transport polymer in contact with the pigment layer. A method for producing a photoreceptor comprises depositing a layer of sensitizing electron donor material in a polymer binder on a substrate. An extrinsic pigment layer is deposited on the layer of sensitizing electron donor material. A charge transport layer is deposited on the pigment layer.
The appropriate components and process aspects of the each of the foregoing U.S. Patents may be selected for the present disclosure in embodiments thereof.